Cartridges for use in an electrophotographic image forming apparatus are known. Such cartridges may include a housing, a photoconductor drum, a transfer roller, and a transfer electrode for applying a voltage to the transfer roller. The photoconductor drum, the transfer roller and the transfer electrode may all be mounted in the housing (see, e.g., Japanese Unexamined Patent Application Publication No. 2006-330620). In particular examples, the transfer roller is disposed under the photoconductor drum and is arranged in opposing relation to the photoconductor drum in pressure contact. Further, the voltage is applied to the transfer roller through the transfer electrode, which is connected to a controller disposed inside an apparatus body and which is brought into contact with the end of a shaft of the transfer roller in a direction extending from the outer side toward the inner side in the axial direction of the transfer roller.